The present disclosure generally relates to electronic devices and, more particularly, to reference voltage stabilization apparatuses
In electronic circuits, a stable reference voltage signal is essential to keep the circuit blocks functioning normally. The circuit blocks may comprise active elements, passive elements, and other suitable circuit elements. When the reference voltage signal is provided to the circuit block, trembles or glitches, however, may occur because of the limited driving capability of the reference voltage signal. The circuit block may need to wait a period of time before the reference voltage signal settles (i.e., becomes stable) so as to function correctly according to the settled reference voltage signal. The operation speed of the circuit block is therefore confined because of the settling time of the reference voltage signal. The sentence “reference voltage signal settles” mentioned above means the reference voltage signal is suitable for the circuit block to refer and function accordingly.
To reduce the influence of the glitches and trembles, the reference voltage signal is usually coupled with the voltage buffer before providing to the circuit block. The voltage buffer has higher driving capability to drive the circuit block and therefore provides a more stable reference voltage signal. For example, the voltage buffer may be realized with unity gain amplifiers.
In some circumstances, the voltage buffer still may not provide enough driving capability, e.g., when the impedance of the load increases or the time for driving the load decreases. Several improvements may be needed for providing a stable reference voltage signal to the load, e.g., increasing the bandwidth of the voltage buffer, lowering the output impedance of the voltage buffer, and dynamically varying the output current of the voltage buffer. Therefore, the hardware of the voltage buffer and the consumed power both increase quadratically and result in the waste of hardware cost and energy.